This is by far the most important thing you need to do to sort out your diet. I was given this advice by my Uncle Dann, a respected urologist. Although I had tested a lot of foods before I did this and followed the advice by the IC sites about diet, I really had no idea how many of the foods that I thought were okay were causing me an incredible amount of pain. Diet is crucial to bringing down your pain level and you cannot leave this part out of your pain plan. I know women who have done that and complain about still being in tons of pain. You have to take responsibility for this part of your life if you want to reach/maintain functionality. It's upsetting, I know. I have not had one bite of chocolate in over three years and it's not fun, but once you do the elimination diet and then try something that flares you, you'll never want to eat it again, trust me!
The elimination diet requires you to calm down your bladder through eating an extremely bland mono-diet for 7-12 days. This bland diet contains plain oatmeal (with NO additives; only one ingredient). You can use a bit of sea salt when cooking it, and please cook it with filtered water, but that's it. This start to the diet is extremely frustrating and I remember crying a couple of times during it but it made my pain level go way down and calmed my bladder so I could start testing foods and see if they were painful or not. Introduce one food at a time and eat it for 2-3 days. Only introduce single ingredients, e.g. organic red peppers, not casserole. If it does not increase your pain level, you can consider it okay and move on to the next food. Make sure to keep a list of which foods are okay and which ones aren't. When you come upon a food that is not okay and it puts you in a flare, do not test anymore foods until the flare is gone. This is a very time-consuming process but it is the best way to figure out what you can eat.
When you find a food that instantly flares you, mix a maximum 1/2 tsp of baking soda with water and drink it. I usually take about 1/8 tsp of baking soda and that's enough. This neutralizes the bladder and helps the pain, especially if the reaction is due to acidic content. I should warn you, this is disgusting. Don't start with a full 1/2 tsp because you will probably throw up immediately. Never take more than that in 24 hrs.
One thing that my uncle didn't tell me but that I will tell you, is to go about your days armed with Prelief®, especially during testing times. Prelief® is an acid reducer that ICers swear by and I could not eat most of the foods I eat without it. It says to take two but I have found that I have to adjust the number to the food I'm eating. For example, for organic blueberries, I take five. For an organic pear, I take three. You can usually feel if you need more. However, if you have taken over six or seven and it still hurts, I'd say you can go ahead and file that food under the foods you can't eat.
Where to start? Check out the IC websites I have listed under the helpful sites on the side to get an idea of which foods are most likely to be okay, and start with them.
It will be different for everyone, but the first foods that I could eat were lactose-free skim milk, organic corn, organic blueberries, and make-shift cornbread (without egg yolks).
The elimination diet is a big thing to take on but it was the best thing I did. Without it, although I eliminated the most instant flaring agents such as lemon juice and coffee, I was still keeping myself at a very stable high pain level. The elimination diet was the only thing that made me realize what I could really eat without pain and I am so grateful to my Uncle Dann and to the process for that.
Please post any comments or questions, and even vent about how frustrating this process is if you'd like, I understand and am happy to listen and offer support. Good luck!!!